const uuid = function (format) {
    var s = [];
    var hexDigits = "0123456789abcdef";
    for (var i = 0; i < 36; i++) {
      s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
    }
    s[14] = "4"; 
    s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); 
    s[8] = s[13] = s[18] = s[23] = "-";
    
    var uuid = s.join("");
    if (format) {
      return uuid.split("-").join("")
    }
    return uuid
  }
   
  module.exports = {
      uuid
  }